You need to abide by the terms of the SPA which both parties have signed. Look at the time given to the vendor to comply with the transfer of ownership of the other half-share. 6 months? 9? Until then, you can't fault him at all. You ought to be aware when you're buying this particular property that it is not the run-of-the-mill transaction and that it may be delayed.  So, do be patient.

With regard to your statement that the owner has 10% and thus, it would benefit him more to delay the process - that is an incorrect statement. The longer the delay, the more detrimental it is to the vendor as the price of the property may appreciate, and he can't do anything about it. Add in inflation and you'll see that the vendor has no reason to delay things. He would definitely want to use the balance 90% for other matters as well.

If you're confused about the whole process then it's time to speak your lawyer directly and find out the latest status and also the flow of proceedings. Some enlightenment would be useful, as you're a first time buyer. Good luck.

JMB is responsible to maintain the safety and security of room itself. Normally a padlocked is placed and the keys kept with management. This falls under the common property. Am not saying that they are responsible for the cables, but when they fail to ensure the security of the room, they would responsible for any damage/loss caused to anything in the room due to their negligence.