It's not so bad, I'm doing the exact same thing 3 times a week now. If it's the second floor of Soda, it can be a little worse since the elevator is super crowded around class-changing time, so I highly advice using the stairs instead.
If it's not the second floor, and you just want to go to 145/155 (i.e. the popular, big lecture room), then it's doable in 7 minutes downhill. Just cross the street right across from Soda (aka don't go down to the intersection of Hearst and Euclid and wait for the green light there), then run across memorial glade past Moffitt to Dwinelle. If it's not 145/155, you can still make it in ~10-15 minutes and you may be a little late, but meh. Just time yourself like failure622 said.
Also, if the class at Soda is the lab/discussion, they usually let you out early, especially the lab if you can finish early and get checked off. No worries tbh.