1. Yeonjo gets the poison and puts it in Heeryang liquors to mask the taste and smell.
2. Heeryang notices its been poisoned and he knows Yeonjo is doing it.
3. Heeryang tells Yeonjo that he knows the liqour is poisoned and still drinks the poisoned liqour.
4. Yeonjo freaks out and regrets decision as he watches and waits with a pounding heart to see Heeryang die. He panics, calls for a doctor, apologizes, realizes he might actually loose Heeryang. Tells him he loves him.
5. Heeryang keeps Yeonjo still in his lap so he can't get help. He doesn't allow him to move so Yeonjo can see what his revenge is going to cost the both of them.
6. Seconds turn into minutes but Heeryang doesn't die because he's smarter than that. He's been taking small amounts of poison for YEARS. This isn't the first time soemone has tried this and probably wont be the last. It's not going to work on him but he's happy to see Yeonjos real feelings for him.
7. They now have to deal with the consequences of knowing they both love eachother.