Okay...First Time I've Seen This Happen
 

The biggest problem with playing both SH4 and SH5 is that, as we all know, the interfaces are different. For instance, on SH4 you just hit the dive button and under you go. With SH5, you have to get below, first, before your boat will dive. Usually!
So I'm playing one of the quick missions and here comes a destroyer. Okay, I hit "V". OOOPS! I forgot to climb into the U-Boat. Didn't matter. The sub starts diving and in seconds I'm earlobes deep in water. And I can't get back in the sub! Lol!!!!! Needless to say, I drowned.
Now, I thought that wasn't supposed to happen. Has anyone else run into that?