What would be your pastoral approach to a minister in training who denied penal substitution and a professor at an evangelical college or seminary who held the same views?
I would be patient with a student and try to persuade them of the biblical standpoint. Patience is initially the right stance for a professor as well. But if a professor comes to a settled conviction against penal substitution, he should be removed from his position in my judgment.
Some brief comments.
1. Implicit in the question and answer is the fact that "evangelical" is a term being employed with some minimal confessional content. So by referring to an "evangelical college or seminary" that is taken as shorthand for an institution that has an evangelical statement of faith.
2. This minimal confessional content would include a clear affirmation of the doctrines of sin, judgment, wrath, atonement, and substitution. These words need not be joined together to form a phrase such as "penal substitutionary atonement," but the presence of the doctrines I have listed would be sufficient to articulate the doctrine. As an example the UCCF doctrinal basis affirms that:
Since the fall, the whole of humankind is sinful and guilty, so that everyone is subject to God's wrath and condemnation.
Sinful human beings are redeemed from the guilt, penalty and power of sin only through the sacrificial death once and for all time of their representative and substitute, Jesus Christ, the only mediator between them and God.
3. An evangelical college or seminary with a statement of faith would work on a voluntary association principle. If this is what you believe then you may teach here. If your views change then you are morally obligated to teach elsewhere. If you are agreeing to the statement of faith but interpreting it in a way that contradicts what it affirms (and it should be added, if your interpretation subverts the meaning attributed to it by the founders of the institution or compilers of the statement) then you are agreeing to it under false pretenses. There is real integrity is someone saying "I don't believe this, therefore I shouldn't teach here anymore," or "my views have changed and I can in all honesty no longer uphold this statement." But there is no moral integrity in verbally assenting to a statement whilst in actual fact undermining it.
4. There is no curb placed on academic freedom in the voluntary association principle that has not been self chosen. Teaching at an evangelical institution is a choice. The choice has been made to teach what is in accordance with the institution's basis of faith. There are other places where one can teach that do not require an agreement to a confessional statement, or a confessional statement that is inclusive enough to accommodate views that would be ruled out by evangelical institutions.
5. Even if you teach in areas not directly covered by the evangelical basis of faith of that particular institution, or if you teach in an area covered by part of the statement, teaching at that evangelical institution still requires a full affirmation of the statement of faith. You are morally obligated to be faithful to the agreement that you have made. When I taught a first year module in apologetics at WEST I was required to uphold and not contradict the school's doctrinal basis. For me to denigrate in any shape or form that doctrinal basis would be sin. Even if I privately denied one or more points of the doctrinal basis, having come to a "settled conviction" against those points, I would still be morally obligated to withdraw from teaching.
6. Not to uphold voluntary association in this way, with its requirement of confessional agreement and subscription, is a sure way to create "doctrinal indifferentism." It is to treat binding theological agreements as if they were of no consequence. Not only is this intellectually dishonest it is also morally reprehensible.