The Lord instructed us not to kill.
No killing is good. Peace or war.
War and killing in a war, while deemed a necessity is still not good, nor a preferred event. It is done in order to safeguard lives.
Assisted suicide does not safeguard a life. It ends one.
Yes, it may end the person's pain and misery. However, an unwanted pregnancy also causes misery and pain....so, is abortion okay in that case?
I completely understand the dilemma. It's a horrible position to be in.
I hope and pray nobody ever finds it preferable to end their life, over living it.
However, God said NO. No killing.
Therefore, as the OP is inquiring about Orthodoxy and assisted suicide....the answer is NO.