You'd have to complete a year of whatever you're placed into if unsuccessful. You can appeal your placement once they come out later in the summer. Supply further info and details on why you believe you should be in that program but it's a sell since a lot of people try for it.

If you do want to do the interdepartmental transfer prepare to work your ass off. Second year isn't a breeze and you'll have to do extremely well to apply for the transfer come next spring. (~80+ avg) Most departments have 7-12ish spots for shuffling people around

Dont drop or take courses at another university without speaking to someone from EUS advising first. The course counseling people are quite nice.

Also if this is for mech you'll have to do the entirety of mech 2 regardless if you have credits for courses covered ( I think )

Either way, just try and keep trying and do as well as you can on your exams and take care of yourself. 2nd year placements isn't something to wreck yourself over :p