*Answer begins here:
YES. The reasons can easily by explained.
FIRST. Is the Senate building being rented? If yes, then the people are paying for the rental. Is the Senate building owned by the government? If yes, then it belongs to the People. There is no law expressly making the premises of the senate a safe haven for fugitives or those charged with the commission of a crime.
SECOND. No senator has any proprietary interest in that building. No senator owns it. It is not a fortress designed to protect erring people from authorities or a foreign embassy where Philippine Law has waived jurisdiction. A criminal or a fugitive from justice can be arrested inside the building.
THIRD. A senator is only immune from arrest while the Senate is in session and if the penalty of the alleged crime is below six (6) years imprisonment. According to Republic Act No. 9851, crime against humanity where death occured is punishable by reclusion perpetua ( 40 years).
FOURTH. Republic Act No. 9851 provides that the Philippines can allow an international tribunal to investigate or try a persons charged of crime against humanity if it is already investigating or trying such persons and, if need be, deliver the said persons to the tribunal. ( Section 17) . This is in accordance with the generally accepted principle of law declaring that crime against humanity is a universal crime. By the way, generally accepted principles of law according to our constitution are adopted by our country as part of the law of the land.
FIFTH. The warrant of arrest of the ICC is valid. The bill of rights of the Constitution provides that no one can be arrested without a warrant of arrest issued by a judge. The word "judge" is not qualified and hence it can refer to a local judge or a foreign judge whose jurisdiction the Philippines has accepted.
SIXTH. Crime against Humanity involves an international element where the Executive Department must be given the greatest respect in its determination and enforcement. Foreign policy, peace and order, apprehension of a fugitive are executive functions. The Legislature should not interfere in the performance of such executive functions as this would violate the separation of powers.
SEVENTH. NBI personnel are within their rights to run after a fugitive from justice or persons charged with a crime. Also, there is a presumption of regularity of government enforcements.
EIGHT. The Senate must NOT coddle and protect a fugitive. That is obstruction of justice. No one is above the law.
NINTH. There is no law expressly providing a so-called " Senate Protective-Custody" as an exemption to the enforcement of a warrant of arrest.
TENTH. Unless stopped by the Supreme Court, the enforcement of a valid arrest must proceed. No one is above the law.
*Answer ends here.