If tyhe Enterprise had changed course, the Boseman would have emerge, hit nothing, and found themselves in the future.
The Boseman "looped" exactly as many times as the Enterprise did. When the Enterprise exploded and reset (how many hours?) the Boseman still being in the area of the explosion also reset the same time period.
I did the math years ago, given the main shuttle bay door size, the general size of the flight deck and assuming the bay was initially at sea level pressure, there would have been enough thrust from the escaping air (combined with the tractor beam) to push the Enterprise out of the immediate path of the Boseman, it was a glancing blow.
The "combined with the tractor beam" is the unknown variable you get toss in there in order to make the process work, though. The thing is the tractor beam was not used decompressing the shuttle bay was done instead
of using the tractor beam. And there's not enough air in the main shuttle bay to move the mass of the Enterprise out of the way and certainly not in any meaningful rate to push the ship out of the way in time.
And yeah the "we can't turn back it might be what gets us in trouble" argument doesn't hold up. Considering the first time through the loop they'd have no reason to change course and staying on course is what got them into the predicament. Changing course is the right thing to do.