I have 1997 Subaru Legacy Outback. If the timing belt breaks, will it destroy the engine? I've heard some engines will be destroyed, while others will not.

I have a two slow oil leaks I took to the mechanic for him to look at. I’m about to leave for a seven day road trip. He says because one of the leaks appears to be coming out around the timing belt cover, he’s worried that the belt will get oil on it and it will slip and fail and that it’s not “safe.” I had oil leaks for years with this car and never had any problem other than some smoke from oil dripping on the exhaust manifold. Two years ago my mechanic fixed about six oil leaks. These are two new ones. I think it’s rather unlikely this slow drip will lead to catastrophe on my road trip. Other opinions?