As a fellow med student I feel qualified to comment on this.
When you say you lack time, that can mean that you lack continuous stretches of uninterrupted time or that you lack frequent unscheduled periods.
Whatever the circumstance I intend to talk to you about a few things that have seriously improved my exercise time efficiency.
Bodyweight fitness:
No matter what your circumstance you have enough time for it. I don't know what your level of fitness is currently, but if you aren't already fairly jacked there's a lot of progress you can make just by doing push ups, pull ups, dips, rows, squats, lunges and planks throughout the day. If you study at home, you can literally superset study and training. Go to the gym a few times a week for 10 minutes to do some squats, deadlifts and wrist roller and that could literally be all you need, depending on your goals.
Workout time savers:
If you actually count the seconds, most of any given person's time in a gym is spent standing around waiting between sets. A set of any exercise takes less than 30 seconds, but people spend multiple minutes resting between sets, thus making it the numerical majority of time spent exercising. If you are short on time, rest time is therefore your enemy.
Good ways I've found to get around rest time include doing supersets and doing fewer, longer sets overall.
The simplest and easiest way I found involved doing 1 set per exercise, as many reps as possible, with a rep goal in mind. For example, let's say it's chest day and I am benching 135 (arbitrarily) and my rep goal is 20. Every chest day, I would go in and bench 135 for one set, as many reps as I could. Chest day over. Once I hit 20 reps, I'd add 5-10 lbs and do it all again.
Speaking from experience, 20 reps seems to be the minimum cutoff for gaining strength that way, whereas a rep goal more like 40-50 gives a far better pump and may be more conducive to hypertrophy.
Your current routine that you've written out looks really good to me as routines go, but that crap would keep you in the gym forever compared to some things I could think up.
Back/Bi/forearms: * Deadlift 1x20 * Yates row 1x40 * Pull ups 1 set to failure or pulldown 1x40 * Barbell shrug 1x40 * Wrist roller 1x40
Chest/tris/abs: * Bench 1x40 * Ab wheel 1x40 (or plank)
Legs/shoulders: * Squat 1x20 * SLDL or good morning 1x40 * Some sort of OHP 1x40 * lat raise 1x40
Each workout will kick your ass in like 10 minutes, then you add weight once you hit the rep goal and move on.
Not saying you have to do it my way, I'm just trying to give you some things to think about.